A typical terminal device is designed such that the display screen backlight can be turned off when the device is not in use for a long period of time, thereby reducing power consumption. When a user operates the terminal device after the backlight is turned off, the backlight is turned on, allowing the user to check information displayed on the display screen and to use an application.
One of the lighting techniques pertaining to methods of lighting a backlight involves a screen display processing device described in Patent Literature 1. The screen display processing device includes two housings attached to each other in a manner capable of opening and closing. When the angle of opening of the two housings is small, the image display processing device reduces the amount of light of the backlight. When the angle of opening is large, the device increases the amount of light.
Accordingly, reducing the opening angle of the housings when a user checks an application and increasing the angle of the housings when the user uses the application can reduce illumination that is brighter than necessary on the display screen, which can, in turn, reduce the power consumption.